Sill corner brackets for coastal impact resistant fenestrations

An impact-resistant fenestration unit comprising:

• a frame assembly comprising a sill, a head jamb, and two opposed side jambs, the frame assembly forming a first lower corner and a second lower corner;
• a first sill corner bracket configured to fit on top of the sill and extend from the first lower corner partway along the top of the sill;
• a second sill corner bracket configured to fit on top of the sill and extend from the second lower corner partway along the top of the sill;
• a bottom sash, the bottom sash comprising a bottom rail, a check rail, and two opposed stiles, the bottom sash configured to move within the frame between a closed position where a bottom portion of the bottom sash engages a top of the sill and an open position where the bottom portion of the bottom sash is separated from the top of the sill;
• the bottom sash forming a first lower corner, a second lower corner, a first upper corner, and a second upper corner;
• the check rail of the bottom sash comprising a surface defining an exterior window side top corner and an interior window side top corner, wherein a radius of curvature of the interior corner is greater than 0.2 inches;
• wherein the impact-resistant fenestration unit exhibits impact resistance properties satisfying ASTM E1996-17 missile level D;
• and
• wherein the impact-resistant fenestration unit exhibits a U factor of less than or equal to 0.40 BTU/h*ft2*° F.

An impact-resistant fenestration unit comprising:

• a frame assembly comprising a sill, a head jamb, and two opposed side jambs, the frame assembly forming a first lower corner and a second lower corner;
• a first sill corner bracket configured to fit on top of the sill and extend from the first lower corner partway along the top of the sill;
• a second sill corner bracket configured to fit on top of the sill and extend from the second lower corner partway along the top of the sill;
• a top sash;
• a bottom sash, the bottom sash comprising a bottom rail, a check rail, and two opposed stiles, the bottom sash configured to move within the frame between a closed position where a bottom portion of the bottom sash engages a top of the sill and an open position where the bottom portion of the bottom sash is separated from the top of the sill;
• the bottom sash forming a first lower corner, a second lower corner, a first upper corner, and a second upper corner;
• the bottom sash comprising a transparent central area and the top sash comprising a transparent central area, wherein the transparent areas cover a surface area of at least 55% of the overall area defined by an outer perimeter of the frame assembly;
• wherein the impact-resistant fenestration unit exhibits impact resistance properties satisfying ASTM E1996-17 missile level D;
• and
• wherein the impact-resistant fenestration unit exhibits a U factor of less than or equal to 0.40 BTU/h*ft2*° F.